The defendant was convicted of armed robbery after a jury trial in the Superior Court. His sole contention on this appeal is that his constitutional right to a fair trial was abridged by the ineffective assistance of his trial counsel. It appears that the constitutional claim is grounded on matters that do not appear on the face of the record and that it may involve the resolution of disputed and unsettled factual questions concerning defense counsel's conduct at the trial. In these circumstances the judgment of conviction must be affirmed and the defendant remitted to his remedy to resolve the factual issues in the Superior Court by an appropriate motion for a new trial. G. L. c. 278, Section 29. Mass.R.Crim.P. 30[b], 378 Mass. 900 (1979). Earl v. Commonwealth, 356 Mass. 181 , 183 (1969). Sayles v. Commonwealth, 373 Mass. 856 (1977). Commonwealth v. Wright, 376 Mass. 725 , 728 n.2 (1978). If he is unsuccessful on that motion he "will retain the right to a full review by [an appellate] court on questions of constitutional interpretation as well as of sufficiency of the evidence to support the trial judge's factual determinations." Earl v. Commonwealth, supra at 183.